[browser] React when a custom data item provider is added/removed

Until now, if a plugin adds a custom data item provider that adds a root item to the browser model, the new root data item would not get added and a restart of QGIS was necessary.
qgis · Apr 20, 2020 · 0633989 · 0633989
1 parent ea9613e
commit 0633989
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diff --git a/python/core/auto_generated/qgsbrowsermodel.sip.in b/python/core/auto_generated/qgsbrowsermodel.sip.in
@@ -9,6 +9,7 @@
 
 
 
+
 class QgsBrowserModel : QAbstractItemModel
 {
 %Docstring

diff --git a/python/core/auto_generated/qgsdataitemproviderregistry.sip.in b/python/core/auto_generated/qgsdataitemproviderregistry.sip.in
@@ -11,7 +11,7 @@
 
 
 
-class QgsDataItemProviderRegistry
+class QgsDataItemProviderRegistry : QObject
 {
 %Docstring
 This class keeps a list of data item providers that may add items to the browser tree.
@@ -63,6 +63,22 @@ Returns the (possibly blank) data provider key for a given data item provider na
 
 :param dataItemProviderName: name of the data item provider
 
+.. versionadded:: 3.14
+%End
+
+  signals:
+
+    void providerAdded( QgsDataItemProvider *provider );
+%Docstring
+Emitted when a new data item provider has been added.
+
+.. versionadded:: 3.14
+%End
+
+    void providerWillBeRemoved( QgsDataItemProvider *provider );
+%Docstring
+Emitted when a data item provider is about to be removed
+
 .. versionadded:: 3.14
 %End
 

diff --git a/src/core/qgsbrowsermodel.cpp b/src/core/qgsbrowsermodel.cpp
@@ -49,6 +49,10 @@ QgsBrowserModel::QgsBrowserModel( QObject *parent )
   : QAbstractItemModel( parent )
 
 {
+  connect( QgsApplication::dataItemProviderRegistry(), &QgsDataItemProviderRegistry::providerAdded,
+           this, &QgsBrowserModel::dataItemProviderAdded );
+  connect( QgsApplication::dataItemProviderRegistry(), &QgsDataItemProviderRegistry::providerWillBeRemoved,
+           this, &QgsBrowserModel::dataItemProviderWillBeRemoved );
 }
 
 QgsBrowserModel::~QgsBrowserModel()
@@ -132,23 +136,9 @@ void QgsBrowserModel::addRootItems()
   const auto constProviders = QgsApplication::dataItemProviderRegistry()->providers();
   for ( QgsDataItemProvider *pr : constProviders )
   {
-    int capabilities = pr->capabilities();
-    if ( capabilities == QgsDataProvider::NoDataCapabilities )
+    if ( QgsDataItem *item = addProviderRootItem( pr ) )
     {
-      QgsDebugMsgLevel( pr->name() + " does not have any dataCapabilities", 4 );
-      continue;
-    }
-
-    QgsDataItem *item = pr->createDataItem( QString(), nullptr );  // empty path -> top level
-    if ( item )
-    {
-      // make sure the top level key is set always
-      item->setProviderKey( pr->name() );
-      // Forward the signal from the root items to the model (and then to the app)
-      connect( item, &QgsDataItem::connectionsChanged, this, &QgsBrowserModel::connectionsChanged );
-      QgsDebugMsgLevel( "Add new top level item : " + item->name(), 4 );
-      setupItemConnections( item );
-      providerMap.insertMulti( capabilities, item );
+      providerMap.insertMulti( pr->capabilities(), item );
     }
   }
 
@@ -182,6 +172,32 @@ void QgsBrowserModel::removeRootItems()
   mDriveItems.clear();
 }
 
+void QgsBrowserModel::dataItemProviderAdded( QgsDataItemProvider *provider )
+{
+  if ( !mInitialized )
+    return;
+
+  if ( QgsDataItem *item = addProviderRootItem( provider ) )
+  {
+    beginInsertRows( QModelIndex(), rowCount(), rowCount() );
+    mRootItems << item;
+    endInsertRows();
+  }
+}
+
+void QgsBrowserModel::dataItemProviderWillBeRemoved( QgsDataItemProvider *provider )
+{
+  const auto constMRootItems = mRootItems;
+  for ( QgsDataItem *item : constMRootItems )
+  {
+    if ( item->providerKey() == provider->name() )
+    {
+      removeRootItem( item );
+      break;  // assuming there is max. 1 root item per provider
+    }
+  }
+}
+
 QMap<QString, QgsDirectoryItem *> QgsBrowserModel::driveItems() const
 {
   return mDriveItems;
@@ -733,3 +749,24 @@ void QgsBrowserModel::removeRootItem( QgsDataItem *item )
   endRemoveRows();
 }
 
+QgsDataItem *QgsBrowserModel::addProviderRootItem( QgsDataItemProvider *pr )
+{
+  int capabilities = pr->capabilities();
+  if ( capabilities == QgsDataProvider::NoDataCapabilities )
+  {
+    QgsDebugMsgLevel( pr->name() + " does not have any dataCapabilities", 4 );
+    return nullptr;
+  }
+
+  QgsDataItem *item = pr->createDataItem( QString(), nullptr );  // empty path -> top level
+  if ( item )
+  {
+    // make sure the top level key is set always
+    item->setProviderKey( pr->name() );
+    // Forward the signal from the root items to the model (and then to the app)
+    connect( item, &QgsDataItem::connectionsChanged, this, &QgsBrowserModel::connectionsChanged );
+    QgsDebugMsgLevel( "Add new top level item : " + item->name(), 4 );
+    setupItemConnections( item );
+  }
+  return item;
+}
diff --git a/src/core/qgsbrowsermodel.h b/src/core/qgsbrowsermodel.h
@@ -25,6 +25,8 @@
 
 #include "qgsdataitem.h"
 
+class QgsDataItemProvider;
+
 /**
  * \ingroup core
  * \class QgsBrowserWatcher
@@ -252,6 +254,10 @@ class CORE_EXPORT QgsBrowserModel : public QAbstractItemModel
     QgsFavoritesItem *mFavorites = nullptr;
     QgsDirectoryItem *mProjectHome = nullptr;
 
+  private slots:
+    void dataItemProviderAdded( QgsDataItemProvider *provider );
+    void dataItemProviderWillBeRemoved( QgsDataItemProvider *provider );
+
   private:
     bool mInitialized = false;
     QMap< QString, QgsDirectoryItem * > mDriveItems;
@@ -260,6 +266,8 @@ class CORE_EXPORT QgsBrowserModel : public QAbstractItemModel
 
     void removeRootItem( QgsDataItem *item );
 
+    QgsDataItem *addProviderRootItem( QgsDataItemProvider *provider );
+
     friend class TestQgsBrowserModel;
     friend class TestQgsBrowserProxyModel;
 };

diff --git a/src/core/qgsdataitemproviderregistry.cpp b/src/core/qgsdataitemproviderregistry.cpp
@@ -66,13 +66,17 @@ void QgsDataItemProviderRegistry::addProvider( QgsDataItemProvider *provider )
     mDataItemProviderOrigin[ provider->name() ] = provider->dataProviderKey();
   }
   mProviders.append( provider );
+  emit providerAdded( provider );
 }
 
 void QgsDataItemProviderRegistry::removeProvider( QgsDataItemProvider *provider )
 {
   int index = mProviders.indexOf( provider );
   if ( index >= 0 )
+  {
+    emit providerWillBeRemoved( provider );
     delete mProviders.takeAt( index );
+  }
 }
 
 QString QgsDataItemProviderRegistry::dataProviderKey( const QString &dataItemProviderName )

diff --git a/src/core/qgsdataitemproviderregistry.h b/src/core/qgsdataitemproviderregistry.h
@@ -18,6 +18,7 @@
 
 #include <QList>
 #include <QMap>
+#include <QObject>
 
 #include "qgis_sip.h"
 
@@ -35,8 +36,9 @@ class QgsDataItemProvider;
  *
  * \since QGIS 2.10
  */
-class CORE_EXPORT QgsDataItemProviderRegistry
+class CORE_EXPORT QgsDataItemProviderRegistry : public QObject
 {
+    Q_OBJECT
   public:
 
     QgsDataItemProviderRegistry();
@@ -79,6 +81,20 @@ class CORE_EXPORT QgsDataItemProviderRegistry
      */
     QString dataProviderKey( const QString &dataItemProviderName );
 
+  signals:
+
+    /**
+     * Emitted when a new data item provider has been added.
+     * \since QGIS 3.14
+     */
+    void providerAdded( QgsDataItemProvider *provider );
+
+    /**
+     * Emitted when a data item provider is about to be removed
+     * \since QGIS 3.14
+     */
+    void providerWillBeRemoved( QgsDataItemProvider *provider );
+
   private:
 #ifdef SIP_RUN
     QgsDataItemProviderRegistry( const QgsDataItemProviderRegistry &rh );

diff --git a/tests/src/core/testqgsbrowsermodel.cpp b/tests/src/core/testqgsbrowsermodel.cpp
@@ -25,6 +25,8 @@
 #include "qgslogger.h"
 #include "qgssettings.h"
 #include "qgsbrowsermodel.h"
+#include "qgsdataitemprovider.h"
+#include "qgsdataitemproviderregistry.h"
 
 class TestQgsBrowserModel : public QObject
 {
@@ -38,6 +40,7 @@ class TestQgsBrowserModel : public QObject
 
     void testModel();
     void driveItems();
+    void updatesToDataItemProviderRegistry();
 
 };
 
@@ -179,5 +182,49 @@ void TestQgsBrowserModel::driveItems()
   QCOMPARE( rootItem->path(), QStringLiteral( "/" ) );
 }
 
+
+class TestDataItemProvider : public QgsDataItemProvider
+{
+  public:
+    QString name() override { return QStringLiteral( "test" ); }
+    int capabilities() const override { return QgsDataProvider::Net; }
+    QgsDataItem *createDataItem( const QString &path, QgsDataItem *parentItem ) override
+    {
+      if ( path.isEmpty() )
+        return new QgsDataItem( QgsDataItem::Custom, parentItem, QStringLiteral( "test-root-item" ), path );
+      return nullptr;
+    }
+};
+
+static int testRootItemCount( QgsBrowserModel &model )
+{
+  int count = 0;
+  for ( int i = 0; i < model.rowCount(); ++i )
+  {
+    if ( model.data( model.index( i, 0 ) ).toString() == QStringLiteral( "test-root-item" ) )
+      ++count;
+  }
+  return count;
+}
+
+void TestQgsBrowserModel::updatesToDataItemProviderRegistry()
+{
+  QgsBrowserModel model;
+  model.initialize();
+
+  QCOMPARE( testRootItemCount( model ), 0 );
+
+  QgsDataItemProvider *provider = new TestDataItemProvider;
+  QgsApplication::dataItemProviderRegistry()->addProvider( provider );
+
+  // browser should react to providerAdded() signal from the registry
+  QCOMPARE( testRootItemCount( model ), 1 );
+
+  QgsApplication::dataItemProviderRegistry()->removeProvider( provider );
+
+  // browser should react to providerWillBeRemoved() signal from the registry
+  QCOMPARE( testRootItemCount( model ), 0 );
+}
+
 QGSTEST_MAIN( TestQgsBrowserModel )
 #include "testqgsbrowsermodel.moc"